1. Field of the Invention
The present invention relates to a thin slider having an excellent design property for use in a slide fastener and more particularly to a thin slider having an automatic locking mechanism with a locking pawl.
2. Description of the Related Art
Conventionally, a slide fastener is attached to an opening in order to open or close the opening in clothes or bags. As one of the sliders for use in such a slide fastener, there has been known, for example, a thin slider having an excellent design property as described in Japanese Design Registration No. 1314704.
As shown in FIG. 10, a thin slider 71 described in Japanese Design Registration No. 1314704 is configured simply of a slider body 76 in which projecting tab attaching portions 75 are disposed on the right and left side faces of the upper blade 72, and a tab 77 pivoted on the right and left tab attaching portions 75, while the front end portions of upper and lower blades 72, 73 are connected to a connecting post. Reduction in thickness of the slider in the vertical direction is achieved by pivoting the tab 77 on the right and left side faces of the upper blade 72 via a tab attaching portion 75.
On the other hand, as a conventional slider for slide fastener, a slider of a type having automatic locking mechanism as disclosed in, for example, U.S. Pat. No. 2,839,806 has been generally known.
A slider 100 described in U.S. Pat. No. 2,839,806, as shown in FIGS. 11 and 12, includes a slider main body 101, a U-shaped bracket 102, a locking pawl 114 supported by the slider main body 101 and a tab 127 attached slidably along the bracket 102.
In the slider main body 101 in U.S. Pat. No. 2,839,806, the front end portions of the upper and lower blades 103, 104 are connected to the connecting post 105 and a hole portion 124 for accommodating a spring 125 for urging the locking pawl 114 is formed in the lower end portion of the connecting post 105. In the central portion in the right and left direction of the slider main body 101, a rib 110 projecting upward from the upper blade and a forked member 111 extending forward of the upper and lower blades 103, 104 are formed integrally. T-shaped members 106, 107 for engaging the U-shaped bracket 102 are erected at the rear mouth end portion of the rib 110.
The U-shaped bracket 102 has a wall portion 130 formed into a U shape and a holding groove portion which is disposed inside the wall portion 130 in order to hold the proximal portion 128 of the tab slidably. The wall portion 130 has an upper leg portion, a lower leg portion and a curved portion for connecting the upper and lower leg portions. Each front end of the upper and lower leg portions has a T-shaped groove portion to which each of the T-shaped members 106, 107 is attached. The upper leg portion of the bracket 102 has a hole portion 121 and a projecting portion 122 is provided on the curved portion adjacent the lower leg portion.
The locking pawl 114 has a pawl lever portion 115 extending backward from a journaling portion 118 which is journaled by the slider main body 101, a first lever portion 126 disposed below the journaling portion 118 and a second lever portion 123 which is disposed above the journaling portion 118 and passes through the hole portion 121 of the U-shaped bracket 102, thereby presenting a substantially T-shaped side view. A pawl portion 117 which can be inserted into/pulled out of an element guide passage 116 in the slider main body 101 is projected from the rear end of the pawl lever portion 115 of the locking pawl 114. The first lever portion 126 of the locking pawl is urged by a spring 125 accommodated in a connecting post 105 of the slider main body 101 in such a direction that the pawl portion 117 of the locking pawl 114 is inserted into the element guide passage 116.
If the slider 100 in U.S. Pat. No. 2,839,806 having such a configuration is employed for a slide fastener, when the slider is locked relative to the element rows without being slid, the locking pawl is urged by the spring 125 as shown in FIG. 12 so that the pawl portion 117 of the locking pawl 114 is inserted into the element guide passage 116. Consequently, the pawl portion 117 of the locking pawl 114 is engaged with the element rows passed through the element guide passage 116 so as to hold the locking position of the slider 100 stably.
For example, if the slider is slid in a direction for decoupling the element rows, the tab 127 is pulled backward of the slider 100. Consequently, the proximal end portion 128 of the tab 127 is moved backward along a holding groove of the U-shaped bracket 102 and comes into contact with an abutment portion 129 of the U-shaped bracket 102. Further, if the tab 127 is pulled backward in a state in which it keeps contact with the abutment 129, the U-shaped bracket 102 is pulled by the proximal end portion 128 of the tab 127 so that the same U-shaped bracket 102 is moved backward of the slider main body 101.
When the U-shaped bracket 102 is moved backward, the projecting portion 122 of the U-shaped bracket 102 presses the first lever portion 126 of the locking pawl 114 so as to rotate the locking pawl 114 resisting an urging force of the spring 125. As a result, the pawl portion 117 of the locking pawl 114 is pulled out of the element guide passage. Then, engaging between the pawl portion 117 and the element row is released to enable the slider 100 to slide smoothly along the element rows.
When an operation of the tab is stopped after the slider 100 is slid to a predetermined position of the element row, the U-shaped bracket 102 is moved to its original position by a force by which the spring 125 urges the locking pawl 114, so that the pawl portion 117 of the locking pawl 114 is inserted into the element guide passage 116. Consequently, the slider 100 can be held at the locking position.
On the other hand, for example, when the slider 100 is slid in a direction for coupling the element rows, the tab 127 is pulled forward of the slider 100 and consequently, the proximal end portion 128 of the tab 127 is moved forward along the holding groove in the U-shaped bracket 102 so that it comes into contact with a wall portion 130 in the center of its curved portion. Further, if the tab 127 is pulled forward while keeping contact with the wall portion 130, the U-shaped bracket 102 is pulled by the proximal end portion 128 of the tab 127, so that the U-shaped bracket 102 is moved forward of the slider main body 101.
Consequently, the side wall face 131 disposed in the hole portion 121 of the U-shaped bracket 102 presses the second lever portion 123 of the locking pawl 114 so as to rotate the locking pawl 114 resisting the urging force of the spring 125 and consequently, the pawl portion 117 of the locking pawl 114 is pulled out of the element guide passage 116. Therefore, the slider 100 can be slid along the element rows smoothly.
According to the slider of U.S. Pat. No. 2,839,806, when the tab 127 of the slider 100 is not operated, the locking state of the slider 100 can be maintained by the locking pawl 114 stably. Further, if the tab 127 is operated to slide the slider 100, the pawl portion 117 of the locking pawl 114 can be pulled out of the element guide passage 116 by operating the tab 127, thereby smoothly sliding the slider 100.
The conventional thin slider 71 (see FIG. 10) as described in Japanese Design Registration No. 566844 is configured as a free slider having no automatic locking mechanism because its design property is taken as more important than its functionality. However, in recent years, as clothes, bags and the like equipped with the slide fastener have become multi-functional and applications of the slide fastener are expanded, the slide fasteners have been demanded to be provided with various functions. For example, the above-mentioned thin slider has been demanded to be equipped with the automatic locking mechanism.
To meet such a demand, it can be considered to employ the automatic locking mechanism described in U.S. Pat. No. 2,839,806 for the thin slider described in Japanese Design Registration No. 566844. In this case, it is necessary to provide the slider body of the thin slider with the locking pawl 114 or the spring 125 described in U.S. Pat. No. 2,839,806 and at the same time, with the U-shaped bracket 102 for pressing the first and second lever portions 126, 123 of the locking pawl 114 when the tab is operated.
However, if the thin slider is provided with the locking pawl 114 or the U-shaped bracket 102 described in U.S. Pat. No. 2,839,806, not only is the thickness of the thin slider in the vertical direction increased, but also the design property is lost, thereby producing such a problem that advantages of the thin slider are eliminated.
According to the slider 100 having the automatic locking mechanism in U.S. Pat. No. 2,839,806, the slider 100 cannot be slid along the element rows until the proximal end portion 128 of the tab 127 is moved along the holding groove in the U-shaped bracket 102 by operating the tab 127 so as to bring the proximal end portion 128 into contact with the abutment portion 129 of the U-shaped bracket 102 or the wall portion 130 in the center of the curved portion. Therefore, the slider 100 in U.S. Pat. No. 2,839,806 has such a drawback that the sliding operation of the slider is delayed with respect to the operation of the tab as compared with the thin slider in Japanese Design Registration No. 566844, whereby leaving a room for improvement in terms of the operability of the slider 100.